The present invention relates generally to vehicle coupling mechanisms and more particularly to such mechanisms wherein a cushioning of end thrust shocks between the vehicle is provided.
The art of interconnecting vehicles in a tractive mode is well established and typically an otherwise rigid coupling including a ball and socket arrangement is employed to permit the two vehicles to swivel angularly relative to one another in negotiating turns to the left or right as well as abruptly encountered inclines. With such coupling schemes any jolt or shock experienced by one of the vehicles is immediately transmitted to the other by way of the coupling resulting in not only annoyance to the driver but also, due to the relatively large masses of the vehicles, great strain on the coupling mechanism.
It has been recognized that a resilient coupling between the vehicles will distribute the effect of an abrupt shock over a longer time interval materially reducing the stress on the coupling mechanism. Prior art schemes have provided spring loading, bump stops at the ends of the coupling travel, multiple resilient bushings and other more complex resilient structures which experience shear during the cushioning action, all of which suffer from one or more of the following defects. Tongue weight and other forces which do not act in the direction of traction are borne by the resilient member. Axial overloads, overloads in the tractive direction, may cause extrusion of a resilient member. Rotation about the axis of traction may occur. They are generally complex, expensive and lacking in ruggedness.